Data processing apparatus, display apparatus, and method of controlling the data processing apparatus

ABSTRACT

A projector includes a coordinate acquiring unit configured to acquire a coordinate of a position pointed by a pointer, a sub-processor configured to render an image on the basis of the coordinate, and a main processor configured to output image data of the image rendered by the sub-processor. The projector performs, according to a predetermined condition, using the main processor, rendering in the same manner as the sub-processor on the basis of the acquired input coordinate, superimposes the rendered image on the rendered image output by the sub-processor to generate a superimposed image, and outputs the superimposed image.

The entire disclosure of Japanese Patent Application Nos. 2012-119427,filed May 25, 2012 and 2012-119428, filed May 25, 2012 are expresslyincorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates to a data processing apparatus thatprocesses image data, a display apparatus, and a method of controllingthe data processing apparatus.

2. Related Art

There has been known a system including a display apparatus such as aprojector and configured to detect, when a user performs position inputoperation using a device such as an electronic pen, a pointed positionand perform rendering or the like (see, for example, JP-A-2011-028629(Patent Literature 1)). In the system described in Patent Literature 1,the display apparatus detects a position pointed by a pointer and acomputer connected to the display apparatus generates a rendered videoon the basis of the detected pointed position. The display apparatus isconfigured to display the rendered video generated by the computer.

In a system that performs rendering on the basis of a pointed positionof position input operation such as the system described in PatentLiterature 1, there is a concern that, when time from operation by auser until display of an image increases, the user feels a sense ofdiscomfort and feeling of operation is deteriorated.

In recent years, a mode for connecting a computer and peripheralequipment by radio communication is spread. However, when the radiocommunication is applied to the system, it is likely that the time untilthe display of a rendered image further increases because of atransmission delay. Therefore, there is a demand for a technique ofmaking it possible to display a rendered image within a short time aftera user performs operation.

SUMMARY

An advantage of some aspect of the invention is to provide a displayapparatus, a display control method, a display system, a data processingapparatus, and a method of controlling the data processing apparatusthat can reduce time from operation by a user until display of an imagerendered on the basis of a pointed position by the operation by theuser.

An aspect of the invention is directed to a data processing apparatusthat outputs image data, the data processing apparatus including: acoordinate acquiring unit configured to acquire an input coordinate; arendering unit configured to render an image on the basis of the inputcoordinate acquired by the coordinate acquiring unit; and an output unitconfigured to output image data of the image rendered by the renderingunit. The output unit is configured to be capable of executingsuperimposition processing for performing rendering in the same manneras the rendering unit on the basis of the input coordinate acquired bythe coordinate acquiring unit, superimposing the rendered image on theimage output by the rendering unit to generate superimposed image data,and outputting the superimposed image data and executes thesuperimposition processing on the basis of a predetermined condition.

According to the aspect of the invention, when one of the rendering unitconfigured to perform rendering and the output unit configured to outputimage data performs the rendering, data of the image rendered on thebasis of the input coordinate is output. Therefore, it is possible toreduce time until the output of the data of the rendered image to matchhigher one of processing speeds of the rendering unit and the outputunit. Consequently, for example, when an image is displayed on the basisof the image data output by the data processing apparatus, it ispossible to reduce time until display of the rendered image.

In the aspect of the invention, the coordinate acquiring unit and theoutput unit may be configured by a first processing device, and therendering unit may be configured by a second processing device providedindependently from the first processing device.

According to this configuration, it is possible to reduce time until thedisplay of the rendered image using an ability of any one processingdevice having higher processing speed among a plurality of processingdevices. Even when time is consumed in a process for inputting the inputcoordinate to the second processing device and a process for outputtingan image from the second processing device to the first processingdevice, data of an image rendered by the first processing device isoutput earlier. Therefore, a delay until the display of the renderedimage does not occur. It is possible to quickly output the image data.

In the aspect of the invention, the output unit may execute thesuperimposition processing for a predetermined time after theacquisition of the input coordinate by the coordinate acquiring unit andthereafter output the image data without superimposing another image onthe image rendered by the rendering unit.

According to this configuration, after the predetermined time elapsesand the image rendered by the rendering unit is input to the outputunit, an un-superimposed image is output. Therefore, even if an image ismade unclear by the superimposition processing, since the image isquickly switched to a clear image, it is possible to preventdeterioration in image quality. Further, it is possible to appropriatelydetermine timing for ending the superimposition processing.

In the aspect of the invention, the output unit may execute thesuperimposition processing after the acquisition of the input coordinateby the coordinate acquiring unit and stop the superimposition processingwhen detecting that an image same as the image rendered by the outputunit is included in the image rendered by the rendering unit.

According to this configuration, an un-superimposed image is outputafter it is detected that the image rendered by the rendering unit isinput to the output unit. Therefore, even if an image is made unclear bythe superimposition processing, since the image is quickly switched to aclear image, it is possible to prevent deterioration in image quality.Further, it is possible to appropriately determine timing for ending thesuperimposition processing.

In the aspect of the invention, the data processing apparatus maydisplay an image on the basis of image data input from an image outputapparatus, and the data processing apparatus may further include: adisplay unit configured to display an image; an input detecting unitconfigured to detect position input operation to calculate an inputcoordinate and output the input coordinate to the image outputapparatus; a rendering unit configured to perform rendering processingfor generating an image on the basis of the input coordinate calculatedby the input detecting unit; and a display control unit configured tosuperimpose the image generated by the rendering unit on the image basedon the image data input from the image output apparatus and cause thedisplay unit to display the image.

According to this configuration, it is possible to cause the imageoutput apparatus, which inputs an image to the display apparatus, toperform rendering of the image based on the input coordinate on thebasis of the coordinate input by the position input operation. Beforethe image data including the image rendered by the image outputapparatus is input, the image generated by the display apparatus isdisplayed. Therefore, even in a period until the image rendered by theimage output apparatus is displayed after the position input operationis detected, it is possible to display the image rendered according tothe position input operation. Consequently, even when a delay occurs intiming when the image data is input to the display apparatus from theimage output apparatus, it is possible to display the image withoutdelay.

In the aspect of the invention, the display control unit may stop,according to a predetermined condition, the superimposed display of theimage generated by the rendering unit.

According to this configuration, when the superimposed display of theimage generated by the display apparatus is unnecessary, for example,when the image data of the image rendered by the image output apparatuson the basis of the input coordinate is input, it is possible to stopthe superimposed display. Consequently, it is possible to display therendered image without hindering the display of the input image from theimage output apparatus and while quickly responding to an input of acoordinate.

In the aspect of the invention, the display control unit may stop thesuperimposed display when a predetermined time elapses after thesuperimposed display of the image generated by the rendering unit isstarted.

According to this configuration, it is possible to superimpose anddisplay the image generated by the display apparatus, for example, onlyin a period until the image data of the image rendered by the imageoutput apparatus on the basis of the input coordinate is input.Therefore, it is possible to display the rendered image withouthindering the display of the input image from the image output apparatusand while quickly responding to an input of a coordinate.

In the aspect of the invention, the display control unit may stop thesuperimposed display when the image data input from the image outputapparatus is image data including an image rendered on the basis of theinput coordinate calculated by the input detecting unit.

According to this configuration, the superimposed display is stoppedwhen the image rendered by the image output apparatus on the basis ofthe input coordinate is included in the image data input from the imageoutput apparatus. Therefore, the image generated by the displayapparatus is superimposed-displayed, for example, only in a period untilthe image rendered by the image output apparatus on the basis of theinput coordinate is input. Therefore, since the image rendered by thedisplay apparatus is displayed until the image rendered by the imageoutput apparatus is displayed only when necessary, it is possible toprevent, for example, deterioration in operability due to an unnecessaryoperation. Even when an image rendered by the display apparatus and animage rendered by the image output apparatus on the basis of the sameinput coordinate are different, it is possible to compensate for a delayin an input of an image without causing a sense of discomfort.

In the aspect of the invention, the display unit may include a lightsource, a modulating unit configured to modulate light emitted by thelight source, and a projecting unit configured to project the lightmodulated by the modulating unit on a projection surface. The inputdetecting unit may detect position input operation on the projectionsurface.

According to this configuration, the display apparatus including theprojecting unit configured to project an image displays the imagerendered according to the input coordinate. Therefore, even when a delayoccurs in the input of the image data from the image output apparatus,it is possible to quickly display an image. For example, even when animage rendered by the display apparatus and an image rendered by theimage output apparatus on the basis of the same input coordinate aredifferent, a sense of discomfort is not caused.

Another aspect of the invention is directed to a display apparatusincluding: a display unit configured to display an image; an inputdetecting unit configured to detect position input operation to acquirean input coordinate; a rendering unit configured to render an image onthe basis of the input coordinate acquired by the input detecting unit;an output unit configured to output image data of the image rendered bythe rendering unit; and a display control unit configured to cause thedisplay unit to display the image on the basis of the image data outputby the output unit. The output unit is configured to be capable ofexecuting superimposition processing for performing rendering in thesame manner as the rendering unit on the basis of the input coordinateacquired by the input detecting unit, superimposing the rendered imageon the image output by the rendering unit to generate superimposed imagedata, and outputting the superimposed image data and executes thesuperimposition processing on the basis of a predetermined condition.

According to this aspect of the invention, when one of the renderingunit configured to perform rendering and the output unit configured tooutput image data performs the rendering, the image rendered on thebasis of the input coordinate is displayed. Therefore, it is possible toreduce time until the display of the rendered image to match higherprocessing speed of processing speeds of the rendering unit and theoutput unit.

Still another aspect of the invention is directed to a method ofcontrolling a data processing apparatus including a main processor and asub-processor, the main processor including a coordinate acquiring unitconfigured to acquire an input coordinate and an output unit configuredto output image data of an image rendered by the sub-processor, and thesub-processor including a rendering unit configured to render an imageon the basis of the input coordinate acquired by the coordinateacquiring unit. The method includes causing, according to apredetermined condition, the main processor to execute superimpositionprocessing for performing rendering in the same manner as the renderingunit on the basis of the input coordinate acquired by the coordinateacquiring unit, superimposing the rendered image on the image output bythe rendering unit to generate superimposed image data, and outputtingthe superimposed image data.

According to this aspect of the invention, when one of the mainprocessor and the sub-processor performs rendering, data of an imagerendered on the basis of the input coordinate is output. Therefore, itis possible to reduce time until the output of data of the renderedimage to match higher one of processing speeds of the main processor andsub-processor. Furthermore, even when time is consumed in a process fortransmitting the input coordinate and the rendered image between themain processor and the sub-processor, data of image rendered by the mainprocessor is output earlier. Therefore, a delay until the display of therendered image does not occur. It is possible to quickly output the dataof the rendered image.

According to the aspects of the invention, it is possible to display theimage rendered according to the position input operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a diagram of the configuration of a projection systemaccording to a first embodiment.

FIG. 2 is a functional block diagram of units included in the projectionsystem.

FIG. 3 is an explanatory diagram showing an example of operation modesof a PC.

FIGS. 4A and 4B are flowcharts for explaining the operation of theprojection system, wherein FIG. 4A is a flowchart for explaining theoperation of the PC and FIG. 4B is a flowchart for explaining theoperation of a projector.

FIG. 5 is a diagram showing the configuration of a projection systemaccording to a second embodiment.

FIG. 6 is a functional block diagram showing the configuration of a mainpart of a projector.

FIG. 7 is an explanatory diagram showing rendering processing executedby the projector.

FIGS. 8A and 8B are flowcharts for explaining the operation of theprojector.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments to which the invention is applied are explained below withreference to the drawings.

First Embodiment

FIG. 1 is a diagram showing the configuration of a projection system 1(a display system) according to an embodiment to which the invention isapplied. The projection system 1 is configured by connecting a PC(personal computer) 100 to a projector 10 set above a screen SC.

The projector 10 (a display apparatus) receives image data transmittedfrom the PC 100 (an image output apparatus) and projects an image basedon the image data on the screen SC functioning as a projection surface.The PC 100 is an external apparatus independent from the projector 10.The PC 100 transmits the image data to the projector 10. The projector10 is a short focus type and is set right above the screen SC. Theprojector 10 projects the image obliquely downward.

The projector 10 not only projects the image based on the image datatransmitted from the PC 100 but also projects, on the screen SC, animage based on image data stored in the inside of the projector 10 andan image generated as explained below in the inside of the projector 10.

The projector 10 can project the image data received from the PC 100irrespective of whether the image data is still image data or movingimage (video) data. The screen SC is not limited to a flat plate fixedto a wall surface. The wall surface itself can also be used as thescreen SC.

In the projection system 1, a user can perform operation using a pointer70 on the screen SC on which the projector 10 projects the image. Thepointer 70 is, for example, a pen-type device. The user uses the pointer70 holding a shaft section 71 by hand and pressing a tip of the pointer70 against the screen SC. An operation switch 72 for detecting pressingoperation is provided at the tip of the pointer 70. When the userpresses the tip of the pointer 70 against the screen SC, the operationswitch 72 is turned on. The user presses the tip of the pointer 70against the screen SC in an arbitrary position on the screen SC toperform position input operation.

As explained below, the projector 10 has a function of detecting theposition of the pointer 70 on the screen SC. When the user performs theposition input operation, a position where the tip of the pointer 70touches the screen SC is detected as a pointed position.

The projection system 1 functions as an interactive whiteboard systemthat receives the position input operation performed by the user withthe pointer 70 and reflects the operation on a projected image.Specifically, when the user performs the position input operation usingthe pointer 70, the projection system 1 detects the position inputoperation and calculates a coordinate of the pointed position. Theprojection system 1 renders a figure such as a straight line, a curvedline, or a polygon according to the calculated coordinate of the pointedposition and projects the rendered figure on the screen SC. In a statein which some image is projected on the screen SC, the projection system1 can render an image to overlap the projected image. The projectionsystem 1 can start rendering of an image after shifting to a state inwhich no image is projected. The image rendered by this function can bestored as image data. Only the rendered image can be stored as imagedata or can be stored as one image data together with the projectedimage projected on the screen SC during the rendering.

In the projection system 1, the projector 10 performs processing fordetecting the position input operation by the pointer 70 and calculatingthe coordinate of the pointed position. The projector 10 transmitsoperation data including the coordinate of the pointed position to thePC 100. The PC 100 receives the operation data from the projector 10,executes rendering processing for generating an image based on thecoordinate included in the operation data, and generates image data fordisplay on the basis of the generated image. The image data for displaymay be image data representing the image itself generated by therendering processing or may be image data obtained by superimposing theimage generated by the rendering processing on another image. The PC 100outputs the generated image data for display to the projector 10.Consequently, the image rendered according to the operation of thepointer 70 is projected on the screen SC like, for example, renderedimages 210 and 211.

A toolbar 201 is projected on the screen SC. On the toolbar 201, aplurality of function buttons 204 and the like for causing the projector10 to execute various functions are arranged. When a positionoverlapping any one of the function buttons 204 is pointed by theoperation of the pointer 70, the projector 10 executes a functionallocated to the function button 204 corresponding to the pointedposition. The toolbar 201 is included in the projected image based onthe image data output by the PC 100. The PC 100 determines whether thepointed position by the pointer 70 overlaps a display position of eachof the buttons of the toolbar 201 and, when the pointed positionoverlaps the display position, the PC 100 executes a function of thebutton corresponding to the pointed position.

On the toolbar 201, for example, a rendering mode switching button 202and a PC operation mode switching button 203 are arranged. The renderingmode switching button 202 is a button for switching an operation mode ofthe PC 100 to an operation mode for performing rendering according tothe operation of the pointer 70 (a rendering mode). On the other hand,the PC operation mode switching button 203 is a button for switching theoperation mode of the PC 100 to an operation mode for using the pointer70 as a pointing device of the PC 100 (a PC operation mode).

In the PC operation mode, the pointer 70 functions as a pointing devicesuch as a mouse or a digitizer. For example, according to the operationof the pointer 70, data operation such as selection, editing, deletion,movement, and copy of data stored by the PC 100 and an executioninstruction for an application program of the PC 100 can be performed.

FIG. 2 is a functional block diagram of the units included in theprojection system 1.

The projector 10 includes an I/F (interface) unit 11 connected to imageoutput apparatuses such as the PC 100, a video reproducing apparatus,and a DVD reproducing apparatus. The I/F unit 11 includes, for example,a wired or wireless USB interface, a wired or wireless LAN interface, aVGA terminal to which an analog video signal is input, a DVI (DigitalVisual Interface) terminal to which digital image data is input, an Svideo terminal to which composite video signals such as NTSC, PAL, andSECAM are input, an RCA terminal to which a composite video signal isinput, a D terminal to which a component video signal is input, and anHDMI connector conforming to an HDMI (registered trademark) standard. Awireless LAN interface 12 for performing radio communication with the PC100 is connected to the I/F unit 11. The wireless LAN interface 12executes a protocol conforming to the IEEE 802.11 standard and transmitsand receives various data between the wireless LAN interface and awireless LAN interface 112 explained below. Consequently, the projector10 and the PC 100 are connected to be capable of transmitting andreceiving data each other.

The projector 10 roughly includes a projecting unit (a display unit)configured to perform formation of an optical image and an imageprocessing system configured to process image data. The projecting unit20 includes an illumination optical system 21, a light modulating device22, and a projection optical system 23. The illumination optical system21 includes a light source configured by a Xenon lamp, an extra-highpressure mercury lamp, an LED (Light Emitting Diode), or a laser lightsource. The illumination optical system 21 may include a reflector andan auxiliary reflector configured to guide light emitted by the lightsource to the light modulating device 22 or may include a lens group(not shown in the figure) or a sheet polarizer for improving an opticalcharacteristic of projected light or a dimming element for reducing alight amount of the light emitted by the light source on a path leadingto the light modulating device 22.

The light modulating device 22 (a modulating unit) includes, forexample, three transmissive liquid crystal panels corresponding to thethree primary colors of RGB and modulates light transmitted through theliquid crystal panels to generate image light. The light from theillumination optical system 21 is separated into color lights of thethree colors of RGB. The color lights are made incident on the liquidcrystal panels corresponding thereto. The color lights transmittedthrough the liquid crystal panels to be modulated are combined by acombination optical system such as a cross-dichroic prism and emitted tothe projection optical system 23.

The projection optical system 23 (a projecting unit) includes a zoomlens for performing enlargement and reduction of an image to beprojected and adjustment of a focus, a motor for zoom adjustment foradjusting a degree of zoom, a motor for focus adjustment for performingadjustment of a focus, and a concave mirror configured to reflectprojected light toward the screen SC. The projection optical system 23performs zoom adjustment and focus adjustment for image light modulatedby the light modulating device 22, guides the light passed through thelens group in the screen SC direction using the concave mirror, andfocuses the light on the screen SC. A projection-optical-system drivingunit 16 configured to drive the motors included in the projectionoptical system 23 according to the control by a control unit 30 and alight-source driving unit 14 configured to drive the light sourceincluded in the illumination optical system 21 according to the controlby the control unit 30 are connected to the projecting unit 20. Aspecific configuration of the projection optical system 23 is notlimited to the example explained above. For example, in a configurationin which the mirror including the concave mirror is not used, it is alsopossible to project the light modulated by the light modulating device22 on the screen SC using a lens and focus the light.

On the other hand, the image processing system mainly includes thecontrol unit 30 configured to integrally control the entire projector10. The image processing system includes a storing unit 35 configured tostore a control program 36 executed by the control unit 30 and dataprocessed by the control unit 30, an operation detecting unit 17configured to detect operation performed via an operation panel 19 and aremote-controller-light receiving unit 18, an image processing unit 40configured to process an input image input via the I/F unit 11, and alight-modulating-device driving unit 15 configured to drive the lightmodulating device 22 and perform rendering on the basis of an imagesignal processed by the image processing unit 40.

The operation detecting unit 17 is connected to theremote-controller-light receiving unit 18 and the operation panel 19.

The remote-controller-light receiving unit 18 receives an infraredsignal transmitted by a remote controller (not shown in the figure) usedby the user of the projector according to button operation. Theremote-controller-light receiving unit 18 decodes the infrared signalreceived from the remote controller, generates operation data indicatingoperation content in the remote controller, and outputs the operationdata to the control unit 30.

The operation panel 19 is provided in an armor housing of the projector10 and includes various switches and an indicator lamp. The operationdetecting unit 17 is controlled by the control unit 30 to turn on orturn on and off the indicator lamp of the operation panel 19 asappropriate according to an operation state or a setting state of theprojector 10. When a switch of the operation panel 19 is operated,operation data corresponding to the operated switch is output from theoperation detecting unit 17 to the control unit 30.

The control unit 30 outputs image data input from the I/F unit 11 to theimage processing unit 40. The image processing unit 40 includes an imageinput unit 41 configured to buffer input image data, a display controlunit 42 configured to execute various kinds of conversion processingsuch as interlace/progressive conversion, resolution conversion, andcolor conversion on the image data as appropriate and generate imagedata of a format set in advance, and a rendering processing unit 43configured to expand an image for each frame in a frame memory 44 on thebasis of the image data processed by the display control unit 42. Theimage processing unit 40 outputs the image data expanded in the framememory 44 to the light-modulating-device driving unit 15.

The rendering processing unit 43 executes overlay rendering forrendering, in the frame memory 44, an image based on image data inputfrom the PC 100 and rendering an image based on image data generated bya rendering control unit 33 explained below to be superimposed on theimage.

The pointer 70 includes a transmission circuit (not shown in the figure)configured to output an infrared signal from a transmission window (notshown in the figure) provided in a shaft section 71. The transmissioncircuit includes a light emitting section such as an infrared LED, alight emission control circuit, and a power supply. In a state in whichthe power supply of the pointer 70 is on, the transmission circuitcyclically transmits the infrared signal according to a systemconforming to, for example, an IrDA standard. The transmission circuitmodulates the infrared signal according to an output state of anoperation state (ON/OFF) of the operation switch 72.

The projector 10 includes a position-input detecting unit 50 configuredto receive the infrared signal transmitted by the pointer 70 and detectthe position of the pointer 70 and an operation state of the operationswitch 72. The position-input detecting unit 50 includes a pointerdetecting unit 54 and a coordinate calculating unit 55 and functions asan operation detecting unit.

The pointer detecting unit 54 includes, for example, an image pickupunit (not shown in the figure) arranged to face the same direction asthe projection optical system 23 and having an angle of view that coversa range in which the projection optical system 23 projects an image onthe screen SC. The image pickup unit includes a light-receiving elementconfigured by a CCD or a CMOS that receives infrared light and aninterface circuit configured to read out and output a detection value ofthe light-receiving element. The pointer detecting unit 54 executesphotographing using the image pickup unit and detects the position ofthe pointer 70 on the basis of photographed image data. The pointerdetecting unit 54 demodulates the received infrared signal to therebydetect the operation state of the operation switch 72. The coordinatecalculating unit 55 calculates, on the basis of the position of thepointer 70 detected by the pointer detecting unit 54, a positioncoordinate of the operation switch 72 with respect to a coordinate axisimaginarily set on the screen SC. The coordinate axis is set on thescreen SC with reference to, for example, a region in which theprojecting unit 20 projects a projected image on the screen SC (aprojection region). Therefore, a coordinate of a pointed position of thepointer 70 in the projection region is calculated by the coordinatecalculating unit 55.

The control unit 30 reads out and executes the control program 36 storedin the storing unit 35 to thereby realize functions of a projectioncontrol unit 31, a detection control unit 32 (an input detecting unit),a rendering control unit 33 (a rendering unit), and an overlay controlunit 34 (a display control unit) and controls the units of the projector10.

The projection control unit 31 detects, on the basis of operation datainput from the operation detecting unit 17, content of operationperformed by an operator and controls the image processing unit 40, thelight-modulating-device driving unit 15, the projection-optical-systemdriving unit 16, and the light-source driving unit 14 according to theoperation to project an image on the screen SC. The projection controlunit 31 controls the projection-optical-system driving unit 16 toexecute focus adjustment, zoom adjustment, diaphragm adjustment, and thelike by the projection optical system 23.

The detection control unit 32 controls the position-input detecting unit50 to detect a pointed position of the pointer 70 and an operation stateof the operation switch 72 included in the pointer 70. Upon detectingthat the operation switch 72 is turned on, the detection control unit 32acquires a coordinate of the pointer 70 at that point and outputs thecoordinate to the rendering control unit 33.

The rendering control unit 33 renders the rendered images 210 and 211(FIG. 1) or the like to follow the operation by the pointer 70 detectedby the detection control unit 32. When the position coordinate of thepointer 70 at the time of turn-on of the operation switch 72 is inputfrom the detection control unit 32, the rendering control unit 33renders a figure or the like having the coordinate as a vertex or anendpoint and generates image data of a rendered image. For example, therendering control unit 33 renders a straight line or a curved lineconnecting a coordinate input last time and a coordinate input this timefrom the detection control unit 32 and generates image data of thestraight line or the curved line.

The rendering control unit 33 acquires attributes of a figure renderedby the PC 100 in the rendering mode and performs rendering according tothe acquire attributes. That is, the rendering control unit 33 detects,from image data input from the PC 100, attributes such as a shape, acolor of a line, and the thickness of the line of the figure rendered bythe PC 100. The rendering control unit 33 renders, on the basis of thecoordinate detected by the detection control unit 32, a figure thatlooks the same as the figure rendered by the PC 100. The renderingcontrol unit 33 may transmit and receive control data concerningattributes of a figure to be rendered between the rendering control unit33 and the PC 100 and determine the attributes of the figure to berendered.

The overlay control unit 34 outputs the image data rendered by therendering control unit 33 to the image processing unit 40 and causes therendering processing unit 43 to superimposed (overlay)-render the imagedata on an image based on the image data received from the PC 100. Whena predetermined condition is met, the overlay control unit 34 stops theoutput of the image data to the image processing unit 40 and causes therendering processing unit 43 to stop the overlay rendering. When theoverlay rendering is stopped, the rendering processing unit 43 renders,in the frame memory 44, only the image based on the image data inputfrom the PC 100. Therefore, only the image based on the image dataoutput from the PC 100 is projected on the screen SC.

The operation for starting and stopping the overlay rendering by theoverlay control unit 34 is explained. When the detection control unit 32detects a coordinate of a pointed position of the pointer 70 and therendering control unit 33 generates image data, the overlay control unit34 quickly causes the rendering processing unit 43 to start the overlayrendering.

Thereafter, the overlay control unit 34 determines whether an imagerendered based on the coordinate detected by the detection control unit32 is included in the image data input from the PC 100. When determiningthat the rendered image is included, the overlay control unit 34 stopsthe overlay rendering. Therefore, the image rendered by the renderingcontrol unit 33 is overlay-rendered after the operation switch 72detects a coordinate until an image rendered by the PC 100 on the basisof the coordinate is input. The determination is performed by detectinga new rendered image in the image data input from the PC 100. Forexample, the overlay control unit 34 calculates a difference betweeninput image data input from the PC 100 when the operation switch 72detects a coordinate of a pointed position of the pointer 70 anew andimage data input thereafter and detects the new rendered image. Theoverlay control unit 34 may determine whether a figure or the like isincluded in the vicinity of the coordinate detected by the detectioncontrol unit 32 in the image data input from the PC 100.

When time from detection of a coordinate by the operation switch 72until an input of an image rendered by the PC 100 on the basis of thecoordinate is known in advance, the overlay control unit 34 may set inadvance time from a start until an end of the overlay rendering. In thiscase, when the set time elapses from the start of the overlay rendering,the overlay control unit 34 stops the overlay rendering.

FIG. 3 is an explanatory diagram showing an example of operation modesof the PC 100.

The PC 100 is capable of switching and executing a plurality ofoperation modes including at least a rendering mode for performingrendering on the basis of a pointed position of the pointer 70 andoperation modes other than the rendering mode. As shown in FIG. 2, inthis embodiment, besides the rendering mode, the PC 100 has a PCoperation mode for treating a coordinate of a pointed position of thepointer 70 as an input coordinate by the pointing device. The PC 100 maybe capable of executing operation modes other than the rendering modeand the PC operation mode.

The switching of the operation modes of the PC 100 is performedaccording to operation by an input device of the PC 100 or operation ofthe rendering mode switching button 202 or the PC operation modeswitching button 203 of the toolbar 201 (FIG. 1).

In the PC operation mode, the PC 100 displays a pointer corresponding toan input coordinate of the pointing device on image data output to theprojector 10. The pointer is, for example, a pointer generally used in apersonal computer. Examples of the pointer include a pointer having anarrow shape.

Only when the PC 100 is executing the “rendering mode” for performingrendering on the basis of a coordinate of a pointed position of thepointer 70, the overlay control unit 34 executes the overlay rendering.As explained above, the PC 100 can switch and execute the rendering modeand the PC operation mode. In the PC operation mode, since the PC 100changes an image output to the projector 10 on the basis of thecoordinate of the pointed position of the pointer 70 in the same manneras the case of the operation of the pointing device, the PC 100 does notperform rendering based on the coordinate of the pointed position.Therefore, the overlay control unit 34 has a function of determiningwhether the PC 100 is in the rendering mode. Only while the PC 100 is inthe rendering mode, the overlay control unit 34 starts the overlayrendering.

The overlay control unit 34 determines, for example, on the basis of apointer included in image data input from the PC 100, whether the PC 100is in the rendering mode or the PC operation mode. In an example shownin FIG. 2, when an arrow-shaped pointer is included in input image dataof the PC 100, the overlay control unit 34 determines that the PC 100 isoperating in the PC operation mode. When the arrow-shaped pointer is notincluded in the input image data, the overlay control unit 34 determinesthat the PC 100 is operating in the rendering mode.

The PC 100 includes a control unit 101 configured to centrally controlthe units of the PC 100. The control unit 101 is realized by, forexample, a CPU, a ROM having stored therein a basic control program andthe like executed by the CPU, and a RAM that temporarily stores programsexecuted by the CPU, data processed by the CPU, and the like. The PC 100includes an input unit 106 configured to detect input operation by aninput device including pointing devices such as a keyboard and a mouse,a display control unit 107 configured to cause a monitor (a displayunit) 108 to display content of the input operation detected by theinput unit 106, a processing result by the control unit 101, and thelike, an external interface 109 connected to an external apparatus suchas the projector 10, and a storing unit 110 configured to store variousprograms including a control program 111 executed by the control unit101, data processed by the programs, and the like. A wireless LANinterface 112 configured the same as the wireless LAN interface 12 isconnected to the external interface 109. The external interface 109 iscapable of executing radio communication with the I/F unit 11.

The control unit 101 executes the control program 111 to thereby realizefunctions of an apparatus control unit 102, an image selecting unit 103,an image output unit 104, and a rendering processing unit 105.

The apparatus control unit 102 executes, for example, processing forcontrolling the projector 10 in the PC operation mode and processing forreceiving data transmitted from the projector 10. The apparatus controlunit 102 controls the operation mode of the PC 100. When the operationmode is designated by operation detected by the input unit 106 and whendetermining that a coordinate input from the projector 10 is operationof the rendering mode switching button 202 or the PC operation modeswitching button 203 of the toolbar 201 (FIG. 1), the apparatus controlunit 102 executes the designated operation mode. In the PC operationmode, the apparatus control unit 102 processes the coordinate input fromthe projector 10 as an input coordinate by the pointing device connectedto the input unit 106. In the rendering mode, the apparatus control unit102 outputs the coordinate input from the projector 10 to the renderingprocessing unit 105 and causes the rendering processing unit 105 toexecute operation of rendering.

Further, the apparatus control unit 102 transmits, in response to arequest transmitted from the projector 10, control data concerningattributes of a figure rendered by the rendering processing unit 105 tothe projector 10.

When image data is output to the projector 10, the image selecting unit103 selects, according to operation detected by the input unit 106, theimage data output to the projector 10. For example, the image selectingunit 103 can select image data directly designated by operation by theuser out of image data (not shown in the figure) stored in the storingunit 110 or can select the image data in the storing unit 110 in orderset in advance.

The image output unit 104 outputs the image data selected by the imageselecting unit 103 to the projector 10. The image output unit 104 mayperform processing for converting the resolution and the frame rate ofthe selected image data according to the specifications of the projector10.

When a coordinate of a pointed position of the pointer 70 is input fromthe apparatus control unit 102 while the PC 100 is executing therendering mode, the rendering processing unit 105 executes renderingprocessing for generating or updating an image according to thecoordinate and outputs image data. The image data output by therendering processing unit 105 is output to the projector 10 by the imageoutput unit 104.

FIGS. 4A and 4B are flowcharts for explaining the operation of theprojection system 1. FIG. 4A is a flowchart for explaining the operationof the PC 100. FIG. 4B is a flowchart for explaining the operation ofthe projector 10. In FIGS. 4A and 4B, in particular, operationsperformed according to the operation of the pointer 70 are shown.

In a state in which the projector 10 and the PC 100 are connected, whenthe PC 100 starts an output of image data (step S11), the projectioncontrol unit 31 of the projector 10 acquires the image data input fromthe PC 100, renders an image in the frame memory 44 on the basis of theimage data, and projects the image using the projecting unit 20 (stepS21). The detection control unit 32 of the projector 10 starts detectionof the position of the pointer 70 and detection of the operation of theoperation switch 72 (step S22) and stays on standby until the detectioncontrol unit 32 detects the operation (step S23).

Upon detecting the operation by the pointer 70 (Yes in step S23), thedetection control unit 32 detects the position of the tip of the pointer70 during the operation and calculates a coordinate of the detectedposition (step S24). Further, the detection control unit 32 generatesoperation data including the calculated coordinate and outputs theoperation data to the PC 100 (step S25).

The control unit 101 of the PC 100 receives and acquires operation datatransmitted from the projector 10 (step S12) and generates image dataaccording to the operation mode being executed by the PC 100 (step S13).When the PC 100 is executing the rendering mode, the renderingprocessing unit 105 renders a figure according to an input coordinateincluded in the received operation data and generates image dataincluding the rendered figure. When the PC 100 is executing the PCoperation mode, the control unit 101 sets the input coordinate includedin the received operation data as an input coordinate of the pointingdevice and receives the operation data as processing data for a file ora folder. In this case, the control unit 101 generates, on the basis ofthe input coordinate, image data of an operation screen displayed on themonitor 108 by the PC 100.

The apparatus control unit 102 transmits the generated image data to theprojector 10 via the wireless LAN interface 112 (step S14) anddetermines whether the apparatus control unit 102 ends the operation bythe pointer 70 (step S15). When continuing the operation correspondingto the operation of the pointer 70 (No in step S15), the apparatuscontrol unit 102 returns to step S12 and stays on standby until theapparatus control unit 102 receives operation data. If input operationor the like for instructing the end of the operation of the pointer 70is performed (Yes in step S15), the apparatus control unit 102 ends theprocessing.

The overlay control unit 34 determines whether the operation mode beingexecuted by the PC 100 is the rendering mode (step S26). For example, asexplained above, the overlay control unit 34 detects a pointer includedin image data input from the PC 100 to thereby determine whether theoperation mode being executed by the PC 100 is the rendering mode. Whenthe overlay control unit 34 determines that the PC 100 is not in therendering mode (No in step S26), the operation of the projector 10returns to step S23. On the other hand, when the overlay control unit 34determines that the operation mode of the PC 100 is the rendering mode(Yes in step S26), the rendering control unit 33 acquires attributes ofa figure or the like to be rendered (step S27). The rendering controlunit 33 renders the figure or the like to match the acquired attributesand generates an image to be overlay-displayed (step S28). The overlaycontrol unit 34 causes the rendering processing unit 43 tooverlay-display the image generated by the rendering control unit 33(step S29).

In the operation illustrated in FIGS. 4A and 4B, when time from thestart of the overlay display reaches a predetermined time or when imagedata rendered on the basis of a coordinate detected by the detectioncontrol unit 32 is input from the PC 100, the overlay control unit 34stops the overlay display. That is, the overlay control unit 34determines whether the predetermined time elapses from the start of theoverlay display (step S30). When the predetermined time elapses (Yes instep S30), the overlay control unit 34 shifts to step S33 explainedbelow. When the predetermined time does not elapse (No in step S30), theoverlay control unit 34 determines whether image data including an imagerendered on the basis of the coordinate detected by the detectioncontrol unit 32 is input from the PC 100 (step S31). When the pertinentimage data is not input (No in step S31), the operation of the projector10 returns to step S23. When the image data including the image renderedon the basis of the input coordinate is input from the PC 100 (Yes instep S31), the overlay control unit 34 projects an image based on theimage data input anew (step S32) and shifts to step S33.

In step S33, the overlay control unit 34 stops the overlay display bythe rendering processing unit 43 and causes the projecting unit 20 toproject only the image based on the image data input from the PC 100.Thereafter, the detection control unit 32 determines whether thedetection control unit 32 ends the detection of the operation by thepointer 70 (step S34). When continuing the detection of the operation(No in step S34), the detection control unit 32 returns to step S23.When input operation or the like for instructing the end of theoperation of the pointer 70 is performed (Yes in step S34), thedetection control unit 32 ends the processing.

As explained above, the projection system 1 according to the embodimentto which the invention is applied includes the PC 100 configured tooutput image data and the projector 10 configured to display an imagebased on the image data output by the PC 100. The projector 10 includesthe detection control unit 32 configured to detect position inputoperation to calculate an input coordinate and output the inputcoordinate to the PC 100, the rendering control unit 33 configured toperform rendering processing for generating an image on the basis of theinput coordinate calculated by the detection control unit 32, and theoverlay control unit 34 configured to superimpose the image generated bythe rendering control unit 33 on an image based on image data output bythe PC 100 and cause the projecting unit 20 to project the image. The PC100 generates an image on the basis of the input coordinate output bythe projector 10 and outputs image data including the generated image tothe projector 10.

Consequently, in the configuration in which the PC 100 renders an imageon the basis of the input coordinate of the position input operation bythe pointer 70 detected by the projector 10 and the projector 10displays the image, the image generated by the projector 10 is displayedbefore the image data including the image rendered by the PC 100 isinput. Therefore, an image rendered according to the operation of thepointer 70 can be displayed even in a period until the image rendered bythe PC 100 is displayed after the projector 10 detects the operation bythe pointer 70. Therefore, even when a delay occurs in timing when theimage data is input to the projector 10 from the PC 100, it is possibleto display the image without delay.

The overlay control unit 34 stops, on the basis of the predeterminedcondition, the superimposed display of the image generated by therendering control unit 33. For example, when the image data includingthe image rendered by the PC 100 on the basis of the input coordinate isinput, the overlay control unit 34 stops the superimposed display. Inthis way, the overlay control unit 34 stops the overlay display, forexample, when it is unnecessary to overlay-display the image generatedby the projector 10. Therefore, the display of the input image from thePC 100 is not prevented. For example, when there is a slight differencebetween a figure or the like rendered by the PC 100 and a figure or thelike rendered by the rendering control unit 33, blurring and the like ofthe figures are seen if these figures are overlay-displayed. As in thisembodiment, the overlay display is immediately stopped when it isunnecessary to perform the overlay display. Consequently, it is possibleto prevent deterioration in the quality of a projected image.

The over lay control unit 34 may stop the superimposed display when apredetermined time elapses after the superimposed display of the imagegenerated by the rendering control unit 33 is started. In this case, asin the case explained above, the image generated by the projector 10 canbe superimposed-displayed only in a period until the image dataincluding the image rendered by the PC 100 on the basis of the inputcoordinate is input. Since timing for stopping the overlay display canbe determined on the basis of time from the start of the overlaydisplay, it is possible to attain efficiency of processing.

The overlay control unit 34 is characterized by stopping thesuperimposed display when image data input from the PC 100 is the imagedata including the image rendered on the basis of the input coordinatecalculated by the detection control unit 32.

According to the embodiment, the superimposed display is stopped whenthe image rendered by the PC 100 on the basis of the input coordinate isincluded in the image data input from the PC 100. Therefore, the imagegenerated by the projector 10 is superimposed-displayed, for example,only in a period until the image rendered on the basis of the inputcoordinate by the PC 100 is input. Therefore, only when necessary, theimage rendered by the projector 10 is displayed until the image renderedby the PC 100 is input. Therefore, it is possible to prevent, forexample, deterioration in operability due to unnecessary operation. Evenwhen an image rendered by the projector 10 and an image rendered by thePC 100 on the basis of the same input coordinate are different, it ispossible to compensate for a delay in an input of an image withoutcausing a sense of discomfort.

In this embodiment, the invention is applied to the projector 10including the illumination optical system 21, the light modulatingdevice 22 configured to modulate light emitted by the illuminationoptical system 21, and the projection optical system 23 configured toproject the light modulated by the light modulating device 22 on thescreen SC. The detection control unit 32 detects position inputoperation on the screen SC. Therefore, it is possible to quickly performrendering and project a rendered figure or the like according tooperation applied to the screen SC by the pointer 70. Therefore, sinceprocessing for rendering and projecting a figure quickly follows theoperation of the pointer 70, it is possible to realize satisfactoryfeeling of operation and achieve improvement of operability. Even if thePC 100 that renders a figure or the like is set in a place apart fromthe projector 10, it is possible to perform rendering quickly respondingto the operation of the pointer 70 irrespective of the magnitude of adelay in transmission of image data from the PC 100 to the projector 10.Therefore, there is an advantage that a degree of freedom is highconcerning setting locations of the projector 10 and the PC 100 and itis easy to secure a setting location including the screen SC.

The PC 100 can execute a plurality of operation modes including therendering mode. When the PC 100 is executing the rendering mode, theoverlay control unit 34 superimposes and displays an image generated bythe rendering control unit 33. Therefore, it is possible to render afigure or the like and perform the overlay display only when renderingby the projector 10 is necessary.

The rendering control unit 33 performs rendering to match attributes ofan image generated by the PC 100 on the basis of an input image.Therefore, a sense of discomfort is not caused when the overlay displayis started and stopped. It is possible to keep satisfactory displayquality.

The embodiment explained above is only an example of a specific form towhich the invention is applied. The embodiment does not limit theinvention. The invention can also be applied as a form different fromthe embodiment. For example, in the example explained in the embodiment,the position-input detecting unit 50 receives infrared light to therebycalculate a coordinate of a pointed position of the pointer 70. However,photographed image data photographed by an image pickup element thatreceives visible light may be processed to calculate a coordinate of apointed position. For example, a pressure-sensitive or capacitance touchpanel that detects contact operation may be arranged to calculate acoordinate of an operation position on the touch panel. In theconfiguration of the embodiment, the pointer 70 is not limited tobar-type and pen-type pointers. Further, a configuration can also beadopted in which a finger of a user is used as a pointer and theprojector 10 detects a pointed position of the finger.

In the embodiment, as the example of the light modulating device 22 thatmodulates light emitted by the light source, the configuration includingthe three transmissive liquid crystal panels corresponding to therespective colors of RGB is explained. However, the invention is notlimited to this example. For example, the light modulating device 22 maybe configured by using three reflective liquid crystal panels, combiningone liquid crystal panel and a color wheel, using three digital mirrordevices (DMD), or combining one digital mirror device and a color wheel.When only one liquid crystal panel or DMD is used as a light modulatingdevice, a member equivalent to a combination optical system such as across-dichroic prism is unnecessary. Besides the liquid crystal paneland the DMD, a light modulating device capable of modulating lightemitted by the light source can be adopted without a problem.

Further, the display apparatus according to the embodiment is notlimited to the projector that projects an image on the screen SC.Various display apparatuses such as self-emitting display apparatusesincluding a liquid crystal monitor or a liquid crystal television thatdisplays an image on a liquid crystal display panel, a monitor apparatusor a television receiver that displays an image on a PDP (plasma displaypanel), and a monitor apparatus or a television receiver that displaysan image on an organic EL display panel called OLED (Organiclight-emitting diode) or OEL (Organic Electro-Luminescence) are alsoincluded in the image display apparatus according to the embodiment. Inthis case, the liquid crystal panel, the plasma display panel, and theorganic EL display panel are equivalent to the display unit.

The functional units of the projection system 1 shown in FIG. 2 indicatefunctional components. A specific embodiment of the functional units isnot specifically limited. That is, hardware individually correspondingto the functional units does not always need to be mounted. It isnaturally possible to adopt a configuration in which one processorexecutes a program to realize functions of a plurality of functionalunits. A part of the functions realized by software in the embodimentmay be realized by hardware or a part of the functions realized byhardware in the embodiment may be realized by software. Besides, thespecific detailed configurations of the other units of the projectionsystem 1 can be arbitrarily changed without departing from the spirit ofthe invention.

Second Embodiment

A second embodiment is explained.

FIG. 5 is a diagram showing the configuration of a projection system 201according to an embodiment to which the invention is applied. Theprojection system 201 is configured to connect a PC (personal computer)2100, which is an external apparatus independent from a projector 210,to the projector 210 set above a screen SC2.

The projector 210 (a display apparatus, a data processing apparatus)projects, on the screen SC2 functioning as a projection surface, animage based on image data input from the PC 2100 functioning as an imageoutput apparatus. The projector 210 is a short focus type and is setright above the screen SC2. The projector 210 projects the imageobliquely downward.

The projector 210 can not only project an image based on image datatransmitted from the PC 2100 but also project, on the screen SC2, animage generated as explained below in the inside of the projector 210.

The projector 210 can project image data received from the PC 2100irrespective of whether the image data is still image data or movingimage (video) data. The screen SC2 is not limited to a flat plate fixedto a wall surface. The wall surface itself can be used as the screenSC2.

In the projection system 201, a user can perform operation using apointer 270 on the screen SC2 on which the projector 210 projects animage. The pointer 270 is, for example, a pen-type device. The user usesthe pointer 270 holding a shaft section 271 by hand and pressing a tipof the pointer 270 against the screen SC2. An operation switch 272 fordetecting pressing operation is provided at the tip of the pointer 270.When the user presses the tip of the pointer 270 against the screen SC2,the operation switch 272 is turned on. The user presses the tip of thepointer 270 against the screen SC2 in an arbitrary position on thescreen SC2 to perform position input operation.

As explained below, the projector 210 has a function of detecting theposition of the pointer 270 on the screen SC2. When the user performsthe position input operation, a position where the tip of the pointer270 touches the screen SC2 is detected as a pointed position.

The projection system 201 functions as an interactive whiteboard systemconfigured to receive the position input operation performed by the userusing the pointer 270 and reflect the operation on a projected image.Specifically, when detecting position input operation performed by theuser, the projection system 201 renders a figure such as a straightline, a curved line, or a polygon according to a pointed position andprojects the rendered figure on the screen SC2. In a state in which someimage is projected on the screen SC2, the projection system 201 canrender an image to overlap the projected image. The projection system201 can start rendering of an image after shifting to a state in whichno image is projected. The image rendered by this function can be storedas image data. Only the rendered image can be stored as image data orcan be stored as one image data together with the projected imageprojected on the screen SC2 during the rendering.

The projection system 201 can execute both of a “PJ mode” in which theprojector 210 executes a function of generating an image according to apointed position of the pointer 270 and projecting the image on theprojector 210 and a “PC mode” in which the PC 2100 executes thefunction. In the “PJ mode”, the projector 210 detects a pointed positionof the pointer 270, generates an image according to the detected pointedposition, and projects the image on the screen SC2.

A toolbar 2201 is projected on the screen SC2 together with a projectedimage. On the toolbar 2201, a plurality of function buttons 2204 and thelike for causing the projector 210 to execute various functions arearranged. When a position overlapping any one of the function buttons2204 is pointed by the operation of the pointer 270, the projector 210executes a function allocated to the function button 2204 correspondingto the pointed position. In an example shown in FIG. 5, on the toolbar2201, a rendering mode switching button 2202 and a PC operation modeswitching button 2203 are arranged. The rendering mode switching button2202 is a button for instructing switching to an operation mode forperforming rendering according to the operation of the pointer 270 (arendering mode). The PC operation mode switching button 2203 is a buttonfor instructing switching to a PC operation mode for using the pointer270 as a pointing device of the PC 2100. When the pointer 270 can beused, the toolbar 2201 is always projected to be superimposed on theprojected image or independently projected.

In this way, in the projection system 201, operation for renderingfigures such as rendered images 2210 and 2211 and operation on the PC2100 can be performed by the operation performed using the pointer 270.

FIG. 6 is a functional block diagram showing a main part configurationof the projector 210 included in the projection system 201.

The projector 210 includes an input interface (not shown in the figure)to which image data D is input from the external apparatuses such as thePC 2100, a video reproducing apparatus, and a DVD reproducing apparatus.The interface includes, for example, a wired or wireless USB interface,a wired or wireless LAN interface, a VGA terminal to which an analogvideo signal is input, a DVI (Digital Visual Interface) terminal towhich digital image data is input, an S video terminal to whichcomposite video signals such as NTSC, PAL, and SECAM are input, an RCAterminal to which a composite video signal is input, a D terminal towhich a component video signal is input, and an HDMI connectorconforming to an HDMI (registered trademark) standard. The projector 210projects an image on the screen SC2 on the basis of the image data Dinput from the interface.

The projector 210 includes a projecting unit 220 configured to form anoptical image and a main processor 211 (a first processing device)configured to process image data. A sub-processor 240 (a secondprocessing device) configured to render figures such as the renderedimages 2210 and 2211 according to the operation of the pointer 270 isconnected to the main processor 211.

Besides the units shown in FIG. 6, the projector 210 includes anonvolatile storing unit having stored therein, in a non-volatilemanner, programs executed by and data processed by the main processor211 and the sub-processor 240, a work memory configured to temporarilystore programs executed by and data processed by the main processor 211and the sub-processor 240, a frame memory configured to retain, in aframe unit, an image projected by the projecting unit 220, an operationdetecting unit configured to detect operation of the operation panel 219and operation by a remote controller (not shown in the figure), and animage pickup unit configured to photograph an image for detecting theposition of the pointer 270 on the screen SC2. However, the units arenot shown in the figure.

The projecting unit 220 (a display unit) includes an illuminationoptical system 221, a light modulating device 222, and a projectionoptical system 223. The illumination optical system 221 includes a lightsource configured by a Xenon lamp, an extra-high pressure mercury lamp,an LED (Light Emitting Diode), or a laser light source. The illuminationoptical system 221 may include a reflector and an auxiliary reflectorconfigured to guide light emitted by the light source to the lightmodulating device 222 or may include a lens group (not shown in thefigure) or a sheet polarizer for improving an optical characteristic ofprojected light or a dimming element for reducing a light amount of thelight emitted by the light source on a path leading to the lightmodulating device 222.

The light modulating device 222 includes, for example, threetransmissive liquid crystal panels corresponding to the three primarycolors of RGB and modulates light transmitted through the liquid crystalpanels to generate image light. The light from the illumination opticalsystem 221 is separated into color lights of the three colors of RGB.The color lights are made incident on the liquid crystal panelscorresponding thereto. The color lights transmitted through the liquidcrystal panels to be modulated are combined by a combination opticalsystem such as a cross-dichroic prism and emitted to the projectionoptical system 223.

The projection optical system 223 includes a zoom lens for performingenlargement and reduction of an image to be projected and adjustment ofa focus, a motor for zoom adjustment for adjusting a degree of zoom, amotor for focus adjustment for performing adjustment of a focus, and aconcave mirror configured to reflect projected light toward the screenSC2. The projection optical system 223 performs zoom adjustment andfocus adjustment for image light modulated by the light modulatingdevice 222, guides the light passed through the lens group in the screenSC2 direction using the concave mirror, and focuses the light on thescreen SC2. A projection-optical-system driving unit 226 configured todrive the motors included in the projection optical system 223 and alight-source driving unit 224 configured to drive the light sourceincluded in the illumination optical system 221 are connected to theprojecting unit 220. A specific configuration of the projection opticalsystem 223 is not limited to the example explained above. For example,in a configuration in which the mirror including the concave mirror isnot used, it is also possible to project the light modulated by thelight modulating device 222 on the screen SC2 using a lens and focus thelight.

The image data D output by the PC 2100 is input to the main processor211. The main processor 211 includes an image input unit 212 configuredto acquire the image data D, an image adjusting unit 213 configured toprocess the image data D acquired by the image input unit 212, an imageretaining unit 214 configured to temporarily retain the image data Dprocessed by the image adjusting unit 213 and output the image data D atpredetermined timing, a superimposition processing unit 215 configuredto perform processing for superimposing an image based on the image dataD output by the image retaining unit 214 and an overlay image explainedbelow, and an image processing unit 216 configured to render an image ina frame unit in a frame memory (not shown in the figure) on the basis ofthe image processed by the superimposition processing unit 215 andoutput the image to the light-modulating-device driving unit 225. Themain processor 211 functions as an output unit and a display controlunit according to the function of the superimposition processing unit215.

The image adjusting unit 213 executes, for example, resolutionconversion processing for converting the resolution of the image data Dacquired by the image input unit 212 to match the resolution of theliquid crystal panels included in the light modulating device 222 andprocessing for converting the frame rate of the image data D.

The main processor 211 includes a coordinate detecting unit 230configured to detect, on the basis of photographed image dataphotographed by a not-shown image pickup unit, operation of the pointer270 performed on the screen SC2. The coordinate detecting unit 230 (aninput detecting unit, a coordinate acquiring unit) includes a pointerdetecting unit 231 configured to detect the position of the pointer 270from the photographed image data and a coordinate calculating unit 232configured to calculate and output a coordinate of the position detectedby the pointer detecting unit 231.

The pointer 270 includes a light-emitting unit such as an infrared LEDconfigured to output an infrared signal, a control circuit configured tocontrol light emission of the infrared LED, and a power supply. Thepointer 270 transmits the infrared signal according to an operationstate (ON/OFF) of the operation switch 272. Therefore, it is possible tophotograph the pointer 270 during operation by photographing the screenSC2 using an image pickup element that receives infrared light.

The coordinate calculating unit 232 calculates a coordinate of aposition pointed on the screen SC2 by the tip of the pointer 270, i.e.,a coordinate of a pointed position. The coordinate calculated by thecoordinate calculating unit 232 is, for example, a coordinate based on aregion where the projecting unit 220 projects a projected image on thescreen SC2 (a projection region).

A dividing and outputting unit 233 configured to divide and output thecoordinate calculated by the coordinate calculating unit 232 isconnected to the coordinate detecting unit 230. Output destinations ofthe dividing and outputting unit 233 are a rendering processing unit 217included in the main processor 211 and the sub-processor 240. Every timethe coordinate calculating unit 232 calculates a coordinate, thedividing and outputting unit 233 outputs the calculated coordinate tothe rendering processing unit 217 and the sub-processor 240. Thecoordinate output to the rendering processing unit 217 and thecoordinate output to the sub-processor 240 are the same coordinate.

The rendering processing unit 217 performs, on the basis of thecoordinate input from the dividing and outputting unit 233, processingfor rendering figures such as the rendered images 2210 and 2211 (FIG.5). An overlay-image retaining unit 218 configured to temporarily retainan image rendered by the rendering processing unit 217 and output theimage to the superimposition processing unit 215 at predetermined timingis connected to the rendering processing unit 217.

The superimposition processing unit 215 acquires image data for oneframe from the image retaining unit 214 and expands the image in amemory (not shown in the figure) on the basis of the image data for oneframe. The superimposition processing unit 215 acquires the renderedimage from the overlay-image retaining unit 218 and overwrites therendered image on the image expanded in the memory to thereby expand asuperimposed image in the memory. The superimposition processing unit215 outputs the image expanded in the memory to the image processingunit 216 and causes the projecting unit 220 to project the image.

On the other hand, the sub-processor 240 includes a renderingapplication 241 (a rendering unit) configured to render figures such asthe rendered images 2210 and 2211 on the basis of the coordinate inputfrom the dividing and outputting unit 233 of the main processor 211, acommunicating unit 242 configured to acquire the coordinate input fromthe dividing and outputting unit 233 and communicate the coordinate tothe rendering application 241, a synchronization control unit 243configured to perform processing for synchronizing a condition forrendering and the like with the main processor 211, and an image outputunit 244 configured to output image data of an image rendered by therendering application 241 to the main processor 211. That is, thesub-processor 240 is a processor for performing rendering based on thecoordinate calculated by the coordinate detecting unit 230 andoutputting a rendered image to the main processor 211.

Besides the image data D, the image data of the rendered image is inputto the image input unit 212 included in the main processor 211 from thesub-processor 240. The image input unit 212 superimposes the image dataD and the image data input from the sub-processor 240 and outputs imagedata of a superimposed image to the image adjusting unit 213. Like theimage data D independently input to the image adjusting unit 213, theimage data is subjected to resolution conversion processing, frame rateconversion processing, and the like in the image adjusting unit 213 andoutput to the image retaining unit 214.

When rendering is performed according to operation by the pointer 270,the projector 210 calculates a coordinate of a pointed position of thepointer 270 using the coordinate detecting unit 230 and executesrendering using the sub-processor 240 on the basis of the coordinate.The projector 210 superimposes a rendered image rendered by thesub-processor 240 on an image based on the image data D input from thePC 2100 and projects a superimposed image on the screen SC2 using thefunction of the projecting unit 220.

In the projector 210, for example, when operation for moving the pointer270 at high speed is performed, in some case, a rendered image followsthe operation of the pointer 270 in a delayed manner. That is, timing ofgeneration and projection of the rendered image is delayed with respectto the operation of the pointer 270. A cause of the delay is consideredto be a delay caused by limitation of band width of a bus that connectsthe main processor 211 and the sub-processor 240 or a delay that occursbecause the image input unit 212 and the image adjusting unit 213 applyprocessing to the image data of the rendered image generated by thesub-processor 240.

Therefore, the projector 210 performs rendering to follow the operationof the pointer 270 using the sub-processor 240 and, on the other hand,performs rendering using the rendering processing unit 217 in the mainprocessor 211 as well. A rendered image rendered by the renderingprocessing unit 217 is input to the superimposition processing unit 215through the overlay-image retaining unit 218. The superimpositionprocessing unit 215 superimposes the image input to the image input unit212 and the image rendered by the rendering processing unit 217.Therefore, the image data D, the rendered image rendered by thesub-processor 240, and the rendered image rendered by the renderingprocessing unit 217 are superimposed and projected.

Processing for performing rendering and projecting a rendered image bythe rendering processing unit 217 is not affected by the band of the busthat connects the main processor 211 and the sub-processor 240 and aprocessing time by the image input unit 212 and the image adjusting unit213. Therefore, the image rendered by the rendering processing unit 217is projected earlier than the projection of the rendered image renderedby the sub-processor 240.

FIG. 7 is an explanatory diagram showing a state of rendering processingexecuted by the projector 210.

In FIG. 7, a sub-processor rendered image (a second image) 2101 is animage rendered by the sub-processor 240 and input to the superimpositionprocessing unit 215. A main processor rendered image (a first image)2102 is an image rendered by the rendering processing unit 217 and inputto the superimposition processing unit 215. A superimposed image 2103 isan image generated by the superimposition processing unit 215 byperforming the superimposition processing.

As explained above, the main processor rendered image 2102 is input tothe superimposition processing unit 215 earlier than the sub-processorrendered image 2101. Therefore, for example, immediately after thecoordinate detecting unit 230 detects the operation of the pointer 270and calculates a coordinate, as shown in FIG. 7, an image 2112, which isa figure extending along the entire track of the pointer 270, isrendered in the main processor rendered image 2102. In the sub-processorrendered image 2101, an image 2111 halfway in rendering of a part of thetrack is rendered.

The image 2111 included in the sub-processor rendered image 2101 ishalfway in rendering because, for example, the rendering by therendering application 241 is delayed by a delay in an output of acoordinate from the dividing and outputting unit 233 to thecommunicating unit 242 or a frame output by the image retaining unit 214is delayed by several frames behind a frame output by the overlay-imageretaining unit 218 due to a delay in transmission until an input ofimage data of a image rendered by the rendering application 241 to theimage input unit 212 and a delay in processing of the image input unit212 and the image adjusting unit 213.

When the superimposition processing unit 215 superimposes thesub-processor rendered image 2101 input from the image retaining unit214 and the main processor rendered image 2102 input from theoverlay-image retaining unit 218, the superimposed image 2103 isgenerated. The superimposed image 2103 includes an image 2113 equivalentto the entire track of the pointer 270 that should be rendered. That is,even if the image 2111 of the sub-processor rendered image 2101 ishalfway in rendering, the image 2113 in a rendering-completed state isgenerated by the superimposition processing unit 215. Therefore, theimage 2113 is projected on the screen SC2 following the operation of thepointer 270 without delay.

In this way, the projector 210 is configured such that, even if a delayoccurs in a process in which the sub-processor 240 renders and projectsan image, the main processor 211 performs rendering and transmits animage through a path in which a delay hardly occurs. The image renderedby the sub-processor 240 and the image rendered by the main processor211 are superimposed and projected, whereby it is possible to render andproject an image without delay.

Attributes of the image 2111 rendered by the rendering application 241and attributes of the image 2112 rendered by the rendering processingunit 217 desirably coincide with each other. When a rendered image isformed by a figure including a straight line and/or a curved line,attributes of the image are line width, a color of the line, the shapeof an endpoint of the line, a color for painting out the figure, and thelike. The synchronization control unit 243 included in the sub-processor240 and the rendering processing unit 217 transmit and receiveinformation concerning attributes of images to be rendered each otherafter a coordinate is input from the dividing and outputting unit 233 orat every predetermined time and match the attributes of the images.Consequently, the projector 210 can render images having the sameattributes in the rendering application 241 and the rendering processingunit 217.

The operation of the overlay-image retaining unit 218 for outputting therendered image of the rendering processing unit 217 to thesuperimposition processing unit 215 is a temporary operation before therendered image of the sub-processor 240 is rendered as an entire imagethat should be rendered. For example, even if a transmission delay or adelay in processing occurs, the image 2111 in the sub-processor renderedimage 2101 shown in FIG. 7 changes to the image 2112 as time passes.Thereafter, it is unnecessary to superimpose the main processor renderedimage 2102 on the sub-processor rendered image 2101. The image 2111 inthe sub-processor rendered image 2101 and the image 2112 in the mainprocessor rendered image 2102 do not always coincide with each other.For example, if interpolation processing or correction processing isperformed in processing for converting resolution, deformation or achange in a color sometimes occurs in a boundary between a figure and abackground. In this case, when the sub-processor rendered image 2101 andthe main processor rendered image 2102 are superimposed, there isconcern about a little deterioration in image quality, for example, anunclear overlapping portion of the image 2111 and the image 2112.Therefore, it is desirable to minimize a frequency and an execution timeof the processing for superimposing the sub-processor rendered image2101 and the main processor rendered image 2102.

Therefore, the projector 210 is configured such that the rendered imageof the rendering processing unit 217 is input to the superimpositionprocessing unit 215 every time the coordinate detecting unit 230 detectsa coordinate of the pointer 270 and, thereafter, when the predeterminedtime elapses, the input of the rendered image from the overlay-imageretaining unit 218 to the superimposition processing unit 215 isstopped. As a result, only the sub-processor rendered image 2101 of thesub-processor rendered image 2101 and the main processor rendered image2102 is output to the superimposition processing unit 215. Therefore,only the sub-processor rendered image 2101 is displayed.

The projector 210 may be configured such that the superimpositionprocessing is not performed when the image 2111 included in thesub-processor rendered image 2101 and the image 2112 included in themain processor rendered image 2102 are substantially the same accordingto the operation of the overlay-image retaining unit 218 or thesuperimposition processing unit 215. In this case, the image 2111 andthe image 2112 are detected and compared. If the image 2111 and theimage 2112 coincide with each other in portions exceeding apredetermined threshold, the superimposition processing is stopped. Inthis case, only the sub-processor rendered image 2101 of thesub-processor rendered image 2101 and the main processor rendered image2102 is displayed.

FIGS. 8A and 8B are flowcharts for explaining the operation of theprojector 210. In particular, processing for performing renderingaccording to the operation of the pointer 270 is explained. FIG. 8A is aflowchart for explaining the operation of the sub-processor 240 and FIG.8B is a flowchart for explaining the operation of the main processor211.

The main processor 211 acquires the image data D input from the PC 2100and starts projection through processing by the image input unit 212 andthe image adjusting unit 213 (step S121). The coordinate detecting unit230 starts detection of the operation of the pointer 270 (step S122) andstays on standby until the operation is detected (step S123).

When the operation by the pointer 270 is detected by the pointerdetecting unit 231 (Yes in step S123), the coordinate detecting unit 230calculates a coordinate of a position detected by the coordinatecalculating unit 232 (step S124). The coordinate calculating unit 232outputs the calculated coordinate to the dividing and outputting unit233. The dividing and outputting unit 233 outputs the coordinate to therendering processing unit 217 and the communicating unit 242 (stepS125).

When the communicating unit 242 acquires the coordinate output from thedividing and outputting unit 233 (step S111), the sub-processor 240starts processing of rendering. The sub-processor 240 synchronizesattributes of an image with the rendering processing unit 217 using thesynchronization control unit 243 (step S112), executes rendering (stepS113), and outputs image data of a rendered image to the image inputunit 212 from the image output unit 244 (step S114). Even while therendering is performed on the basis of the coordinate acquired by thecommunicating unit 242, i.e., before the rendering is completed, thesub-processor 240 outputs the rendered image to the image input unit 212at a period adjusted to a frame rate of the light modulating device 222or a shorter period. Therefore, for example, when time equivalent to twoor more frames is required until the rendering is completed, image datahalfway in the rendering is output to the image input unit 212.

The rendering processing unit 217 of the main processor 211 synchronizesthe synchronization control unit 243 and attributes of the image (stepS126), executes the rendering on the basis of the coordinate input fromthe dividing and outputting unit 233 (step S127), and, after the startof the rendering, outputs the rendered image to the overlay-imageretaining unit 218 at the period adjusted to the frame rate of the lightmodulating device 222 or the shorter period. The overlay-image retainingunit 218 outputs the image data to the superimposition processing unit215 at the period adjusted to the frame rate of the light modulatingdevice 222 or the shorter period. The superimposition processing unit215 superimposes the image input from the overlay-image retaining unit218 and the image input from the image retaining unit 214 and causes theprojecting unit 220 to project a superimposed image (step S128).

The superimposition processing unit 215 stops the superimpositionprocessing when time after the start of the superimposition processingreaches a predetermined time or when the rendered image rendered by thesub-processor 240 substantially coincides with the rendered image of therendering processing unit 217. That is, the superimposition processingunit 215 determines whether the predetermined time elapses after thestart of the superimposition processing (step S129). When thepredetermined time elapses (Yes in step S129), the superimpositionprocessing unit 215 shifts to step S131 explained below. When thepredetermined time does not elapse (No in step S129), thesuperimposition processing unit 215 compares the image input from theimage retaining unit 214 and the image input from the overlay-imageretaining unit 218 and determines whether the images coincide with eachother (step S130). When a difference between the rendered images exceedsa predetermined ratio (No in step S130), the operation of the projector210 returns to step S123.

When the rendered images coincide with each other at a ratio equal to orhigher than the predetermined ratio (Yes in step S130), thesuperimposition processing unit 215 shifts to step S131.

In step S131, the superimposition processing unit 215 stops thesuperimposition (overlay) processing and causes the projecting unit 220to project only the image input from the image retaining unit 214.Thereafter, the main processor 211 determines whether the main processor211 ends the detection of the operation by the pointer 270 (step S132).When continuing the detection of the operation (No in step S132), themain processor 211 returns to step S123. If input operation or the likefor instructing the end of the operation of the pointer 270 is performed(Yes in step S132), the main processor 211 ends the processing.

As explained above, the projector 210 according to the embodiment towhich the invention is applied includes the coordinate detecting unit230 configured to calculate a coordinate of a pointed position pointedby the pointer 270, the sub-processor 240 including the renderingapplication 241 configured to render an image on the basis of thecoordinate output by the coordinate detecting unit 230, and the mainprocessor 211 including the superimposition processing unit 215configured to output image data of the image rendered by the renderingapplication 241. The main processor 211 is configured to be capable ofexecuting superimposition processing for performing, using the renderingprocessing unit 217, superimposition processing for performing, in thesame manner as the rendering application 241, rendering on the basis ofthe coordinate calculated by the coordinate detecting unit 230,superimposing a rendered image on the image output by the renderingapplication 241 to generate superimposed image data, and outputting thesuperimposed image data. The main processor 211 executes thesuperimposition processing on the basis of a predetermined condition.Consequently, when any one of the sub-processor 240 and the mainprocessor 211 performs rendering, a rendered image rendered on the basisof an input coordinate is output and projected on the screen SC2.Therefore, it is possible to reduce time until the output of therendered image to match higher processing speed of processing speeds ofthe main processor 211 and the sub-processor 240.

The projector 210 includes the main processor 211 and the sub-processor240, which are a plurality of processing devices provided independentlyfrom each other. The main processor 211 configures the coordinatedetecting unit 230 and the superimposition processing unit 215. Thesub-processor 240 configures the rendering application 241. Therefore,it is possible to reduce time until the display of the rendered imageusing an ability of any one processor having higher processing speed ofthe main processor 211 and the sub-processor 240.

The main processor 211 executes the superimposition processing for thepredetermined time after the coordinate detecting unit 230 calculates acoordinate and the dividing and outputting unit 233 outputs thecoordinate. Thereafter, the main processor 211 outputs an image withoutsuperimposing another image on the output image of the image retainingunit 214. Therefore, it is possible to minimize a frequency and anexecution time of the superimposition processing.

Further, the main processor 211 stops the superimposition processingwhen an image same as the rendered image of the rendering processingunit 217 is included in the rendered image of the sub-processor 240after the coordinate detecting unit 230 calculates a coordinate and thedividing and outputting unit 233 outputs the coordinate. Therefore, itis possible to minimize a frequency and an execution time of thesuperimposition processing.

The embodiment explained above is only an example of a specific form towhich the invention is applied and does not limit the invention. Theinvention can be applied as a form different from the embodiment. Forexample, in the example explained in the embodiments, a coordinate of apointed position is calculated by receiving infrared light emitted bythe pointer 270. However, photographed image data photographed by animage pickup element that receives visible light may be processed tocalculate a coordinate of a pointed position. For example, apressure-sensitive or capacitance touch panel that detects contactoperation may be arranged to calculate a coordinate of an operationposition on the touch panel.

In the embodiment, as the example of the light modulating device 222that modulates light emitted by the light source, the configurationincluding the three transmissive liquid crystal panels corresponding tothe respective colors of RGB is explained. However, the invention is notlimited to this example. For example, the light modulating device 222may be configured by using three reflective liquid crystal panels,combining one liquid crystal panel and a color wheel, using threedigital mirror devices (DMD), or combining one digital mirror device anda color wheel. When only one liquid crystal panel or DMD is used as alight modulating device, a member equivalent to a combination opticalsystem such as a cross-dichroic prism is unnecessary. Besides the liquidcrystal panel and the DMD, a light modulating device capable ofmodulating light emitted by the light source can be adopted without aproblem.

Further, the display apparatus according to the embodiment is notlimited to the projector that projects an image on the screen SC2.Various display apparatuses such as self-emitting display apparatusesincluding a liquid crystal monitor or a liquid crystal television thatdisplays an image on a liquid crystal display panel, a monitor apparatusor a television receiver that displays an image on a PDP (plasma displaypanel), and a monitor apparatus or a television receiver that displaysan image on an organic EL display panel called OLED (Organiclight-emitting diode) or OEL (Organic Electro-Luminescence) are alsoincluded in the image display apparatus according to the embodiment. Inthis case, the liquid crystal panel, the plasma display panel, and theorganic EL display panel are equivalent to the display unit.

All the functional units included in the main processor 211 and thesub-processor 240 illustrated in FIG. 6 are realized as hardware orsoftware by the main processor 211 and the sub-processor 240. Animplementation form of the functional units is not specifically limited.For example, specifically, the main processor 211 and the sub-processor240 may be configured to realize the functional units by executing apredetermined program. For example, the main processor 211 and thesub-processor 240 may be configured as PLDs (Programmable Logic Devices)and logical blocks may be formed to correspond to the functional unitsshown in FIG. 6. Further, the functional units shown in FIG. 6 may beprovided in the main processor 211 and the sub-processor 240 ashardware. Besides, the specific detailed configurations of the otherunits of the projection system 201 can be arbitrarily changed withoutdeparting from the spirit of the invention. In the configuration of theembodiment, the pointer 270 is not limited to bar-type and pen-typepointers. Further, a configuration can also be adopted in which a fingerof a user is used as a pointer and the projector 210 detects a pointedposition of the finger.

What is claimed is:
 1. A data processing apparatus that outputs imagedata, the data processing apparatus comprising: a coordinate acquiringunit configured to acquire a plurality of input coordinates; a renderingunit configured to render a first image of a figure on the basis of theplurality of input coordinates acquired by the coordinate acquiringunit; and an output unit configured to output image data of the firstimage of the figure rendered by the rendering unit, wherein, prior tocompletion of the rendering of the first image of the figure by therendering unit, the output unit is configured to render a second imageof the figure that is substantially the same as the first image of thefigure on the basis of the plurality of input coordinates acquired bythe coordinate acquiring unit, superimpose the second image of thefigure rendered by the output unit on a partial first image of thefigure output by the rendering unit to generate superimposed image data,the partial first image of the figure including a portion of the firstimage of the figure that is less than the entire first image of thefigure, and output the superimposed image data and execute asuperimposition processing on the basis of a predetermined condition. 2.The data processing apparatus according to claim 1, wherein thecoordinate acquiring unit and the output unit are configured by a firstprocessing device, and the rendering unit is configured by a secondprocessing device provided independently from the first processingdevice.
 3. The data processing apparatus according to claim 1, whereinthe output unit executes the superimposition processing for apredetermined time after the acquisition of the plurality of inputcoordinates by the coordinate acquiring unit and thereafter outputs theimage data without superimposing another image on the first image of thefigure rendered by the rendering unit.
 4. The data processing apparatusaccording to claim 1, wherein the output unit executes thesuperimposition processing after the acquisition of the plurality ofinput coordinates by the coordinate acquiring unit and stops thesuperimposition processing when detecting that the first image of thefigure rendered and output by the rendering unit is the same as thesecond image of the figure rendered by the output unit.
 5. The dataprocessing apparatus according to claim 1, wherein the data processingapparatus displays an image on the basis of image data input from animage output apparatus, and the data processing apparatus furthercomprises: a display unit configured to display an image; an inputdetecting unit configured to detect a position input operation tocalculate a plurality of input coordinates and output the plurality ofinput coordinates to the image output apparatus; a rendering unitconfigured to perform rendering processing for generating an image onthe basis of the plurality of input coordinates calculated by the inputdetecting unit; and a display control unit configured to superimpose theimage generated by the rendering unit on the image based on the imagedata input from the image output apparatus and cause the display unit todisplay the image.
 6. The data processing apparatus according to claim5, wherein the display control unit stops, according to a predeterminedcondition, the superimposed display of the image generated by therendering unit.
 7. The data processing apparatus according to claim 6,wherein the display control unit stops the superimposed display when apredetermined time elapses after the superimposed display of the imagegenerated by the rendering unit is started.
 8. The data processingapparatus according to claim 6, wherein the display control unit stopsthe superimposed display when the image data input from the image outputapparatus is image data including an image rendered on the basis of theplurality of input coordinates calculated by the input detecting unit.9. The data processing apparatus according to claim 5, wherein thedisplay unit includes a light source, a modulating unit configured tomodulate light emitted by the light source, and a projecting unitconfigured to project the light modulated by the modulating unit on aprojection surface, and the input detecting unit detects the positioninput operation on the projection surface.
 10. The data processingapparatus according to claim 1, wherein: the figure comprises a line,and the plurality of input coordinates comprise points on the line. 11.The data processing apparatus according to claim 1, wherein the outputunit renders the second image of the figure while the rendering unitrenders the first image of the figure.
 12. The data processing apparatusaccording to claim 1, further comprising a synchronization control unitthat is configured to synchronize attributes of the first image of thefigure with attributes of the second image of the figure.
 13. A displayapparatus comprising: a display unit configured to display an image; aninput detecting unit configured to detect a position input operation toacquire a plurality of input coordinates; a rendering unit configured torender a first image of a figure on the basis of the plurality of inputcoordinates acquired by the input detecting unit; an output unitconfigured to output image data of the first image of the figurerendered by the rendering unit; and a display control unit configured tocause the display unit to display the image on the basis of the imagedata output by the output unit, wherein, prior to completion of therendering of the first image of the figure by the rendering unit, theoutput unit is configured to render a second image of the figure that issubstantially the same as the first image of the figure on the basis ofthe plurality of input coordinates acquired by the input detecting unit,superimpose the second image of the figure rendered by the output uniton a partial first image of the figure output by the rendering unit togenerate superimposed image data, the partial first image of the figureincluding a portion of the first image of the figure that is less thanthe entire first image of the figure, and output the superimposed imagedata and execute a superimposition processing on the basis of apredetermined condition.
 14. A method of controlling a data processingapparatus including a main processor and a sub-processor, the mainprocessor including a coordinate acquiring unit configured to acquire aplurality of input coordinates and an output unit configured to outputimage data of a first image of a figure rendered by the sub-processor,and the sub-processor including a rendering unit configured to renderthe first image of the figure on the basis of the plurality of inputcoordinates acquired by the coordinate acquiring unit, the methodcomprising causing, according to a predetermined condition, the mainprocessor to execute superimposition processing to render a second imageof the figure that is substantially the same as the first image of thefigure on the basis of the plurality of input coordinates acquired bythe coordinate acquiring unit, superimposing the second image of thefigure rendered by the output unit on a partial first image of thefigure output by the rendering unit to generate superimposed image data,the partial first image of the figure including a portion of the firstimage of the figure that is less than the entire first image of thefigure, and outputting the superimposed image data.